SOLR-5601: Use zkStateReader.getLeaderRetry to find the leader of a newly created temp collection

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1555083 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5577: fix possible race on canceling timer on close

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1555204 13f79535-47bb-0310-9956-ffa450edef68